Yeah, it's too blocky. Kept putting it off as other things rose to the top of the pile for various reasons. Looked at it the other day, but didn't think I could mill the angles into the semi-finished blocks with the clamping equipment on hand.
Then, I wondered if an insert vise would do the trick. Handy work holding devices. Got a couple in various sizes.
Scribed a ten degree taper with a protractor.
The block sat a bit too low in the vise. Settled on using an adjustable parallel.
The parallel sits in the bed of the vise and the work is set on top.
With a protractor, I set up the insert vise at a ten degree angle in the milling vise.
Made passing cuts with a center cutting end mill until hitting the scribed line.
Some Anchor Lube kept the aluminum chips from welding to the cutter.
Flip the part over and flipped the vise to cut the other side.
Once the angles were cut in all three plates, I had to deepen the counter bores for the clamping screws and re-adjust bolt lengths.
A bit more svelte than before.
Relatively happy with it. I'll probably put a matte finish on the sides of the plates when it's not 100 degrees out in the garage.